The present invention relates to a structure for supporting a rotary device for a fuel supply apparatus.
A fuel pump for supplying an internal combustion engine with fuel is installed within a fuel tank of a vehicle or a sub tank accommodated within the fuel tank. The fuel pump comprises a mechanical pump unit and an electromagnetic drive unit (electric motor) for driving the pump unit. The fuel pump is supported in various ways within the sub tank or the fuel tank. For instance, it is supported in such a manner that its axis extends vertically, inclinedly or horizontally.
The electric motor generates vibrations during its rotation, and its first-order and higher-order components of the frequency of rotation cause vibrations of the sub tank or the side walls or bottom wall of a casing, thus generating noise sounds. Therefore, a rubber cushion member made of an oil-resistive rubber material is interposed between the outer peripheral surface of the fuel pump and the bottom wall of the casing. The rubber cushioning member must be rigid or high density-type to some extent to maintain its shape against the weight of the fuel pump and the reaction force of the same generated in response to the fuel discharge operation. As a result, the vibrations cannot be reduced sufficiently.
It is proposed to support the fuel pump from the side wall of the sub tank or the casing while interposing the rubber cushioning member between the outer peripheral surface of the fuel pump and the bottom wall. The side wall of the sub tank or the casing vibrates largely in a direction perpendicular to the side walls, because the vibration absorbing performance of the rubber cushioning member is limited due to its rigid or high density-type construction. Further, the assembling work for fixing the fuel pump to the side wall through the rubber cushioning member is complicated, because the rubber cushioning member must be fixed to both of the fuel pump and the side wall.